1. Field of the Invention
The present invention is broadly concerned with novel coatings that inhibit, and preferably prevent, poisoning by amines released from a dielectric material.
2. Description of the Prior Art
In the field of microelectronic device manufacturing, integration of porous low-k, interlayer dielectrics (ILD) into devices has created situations where the materials or the processing residuals release basic amines. These amines neutralize the photogenerated acid of a photoresist, which, after photolithographic imaging, leaves areas undeveloped or underdeveloped. These low-fidelity images are highly detrimental to the creation of the device because they will degrade device performance or stability and, in some cases, render the device unusable. Left uncontrolled, ILD integration becomes difficult if not impossible. Preventing amines from entering the resist is paramount to the economical creation of the most advanced integrated circuits.
Preventing amine poisoning has not been fully addressed by any process. Several attempts have been made with varying degrees of success. Barrier layers have been used to cap substrates that contain poison. However these barriers are intentionally breached in subsequent processing and allow for local release of poisoning amines. There have been reports of using wet clean or plasma pretreatments to neutralize or destroy the amines prior to the addition of the resist. Although these processes effectively remove the poison, they introduce other steps into the process flow, add expense, or detrimentally affect the properties of the device. Acid neutralization of the base by the application of organic films is not always effective because typical bottom anti-reflective coating technology uses an acid catalyst for the cure and does not prevent poisoning. Furthermore the neutralization is a reversible process whereby the amine may be released during later processing.